Single-Atom Ru-Triggered Lattice Oxygen Redox Mechanism for Enhanced Acidic Water Oxidation

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Activating oxygen anionic redox is key for developing efficient oxygen evolution reaction (OER) electrocatalysts.
• Proton-exchange membrane water electrolyzers (PEMWE) require highly active and durable OER electrocatalysts.

Purpose of the Study:

• To engineer a novel electrocatalyst for enhanced OER activity and stability in PEMWE.
• To investigate the mechanism behind the enhanced catalytic performance.

Main Methods:

• Synthesis of lattice-confined Ru single atoms dispersed on lamellar MnO2.
• In situ spectral characterization.
• Density functional theory (DFT) calculations.

Main Results:

• The Ru-O bond shifted the O 2p band, enhancing metal-oxygen covalency and promoting lattice oxygen oxidation.
• Electron transfer from Mn to Ru alleviated the Jahn-Teller effect, stabilizing the MnO6 octahedral structure.
• The Ru/MnO2 electrocatalyst achieved a low OER overpotential (179 mV at 10 mA cm-2) and exceptional durability (>1000 h at 100 mA cm-2).

Conclusions:

• Engineered Ru/MnO2 exhibits superior OER activity and stability by activating oxygen anionic redox and stabilizing the lattice.
• The developed catalyst demonstrates excellent performance in a PEMWE device, showing low voltage requirements and long-term durability.